In the conventional variable pitch control technology, a generator rotating speed is taken as an input in most cases, a PI controller (proportional integral controller) controls and outputs a variable pitch angle, and then the rotating speed is controlled by a variable pitch executive device.
The traditional PI controller has a simple control structure, and usually acquires a control parameter by means of modeling and adjusting by stimulation software like MATLAB. Since the accuracy of a wind generating set model has a significant influence on the setting result of the control parameter and it is quite difficult to build an accurate model for the kind of large-scale structure with a high degree of nonlinearity like a large wind generating set, the control parameter acquired by means of modeling and adjusting by the stimulation software like MATLAB often differs significantly from an actual wind generating set operational parameter. And generally the PI control method is short of control on dynamic deviation, thus the operating stability of the wind generating set is decreased under the wind condition of quick change of a wind speed.
Overall, the problem of how to acquire an accurate control parameter and how to improve the dynamic variable pitch system action response capability are urgent to resolve at present to the person skilled in the art.